In 2011, three bands set out on a unique 10-day tour from San Francisco to New Orleans. Mumford & Sons, Old Crow Medicine Show and Edward Sharpe & the Magnetic Zeros lived on vintage railcars — singing, partying, playing shows and trying to connect with a lost way of life. At one point, they even discovered a stowaway on the train. A documentary film about that tour, Big Easy Express, won a Grammy this month for best long form music video. The three groups performed a freewheeling folk jam during the trip on Woody Guthrie’s fittingly-titled “This Train Is Bound for Glory.” I can imagine it being sung by a group of Depression-era hobos huddled together in an open box car, yet these contemporary vagabonds chose the sweltering heat of Austin, Texas, for their first — and possibly only — recording of the tune. All aboard for “This Train Is Bound for Glory.”